(a) Field of the Invention
The present invention relates to an apparatus for cutting of sheet metal sheets and for stacking of the separated sections of sheet metal. The apparatus has a metal shear with a metal feed table, at the rear edge of which a fixed lower blade is disposed, which cooperates with an upper blade mounted swivellably between two lateral supports. In the plane of the feed table for the metal, behind the place of cutting, a supporting device, shiftable in its plane perpendicularly to the cutting members and below it, a lifting table which is, adjustable in height is disposed which after withdrawal of the support device, receives the separated section of sheet metal. A stop is provided at a certain adjustable distance behind the lower knife, against which the edge of the sheet metal to be cut, rests in order to determine the width of the sheet metal section thus. After the cut the separated strip of sheet metal lies on the support device and then drops after withdrawal of it downwards onto a stacking surface, so that gradually a stack of sheet metal sections is formed.
Naturally it is desirable that this stack be piled up uniformly and in orderly fashion, in order to avoid subsequently a time consuming and cumbersome manual rearrangement of the stack. This may be achieved by keeping the height of the drop of the section of sheet metal as small as possible. The lift-table adjustable vertically serves this purpose. In practice, a pallet may be used as stacking surface which is disposed on the lifting table. The lifting table is located immediately behind the lower knife and is moved at the start of operation into an upper end position, so that the surface of the pallet lies by a certain, small amount--depending on the thickness of the sheet metal to be cut--below the pallet of the sheet metal feed table. After a few strips of sheet metal are cut and stacked on the pallet, the lift-table is lowered somewhat in order to put the surface of the stack thus formed again into some distance below the plane of the feed table. This process is repeated, until the lift-table has reached its lower end position or the stack its intended height. The lowering of the lifting table may at the same time take place, controlled either manually or automatically, say with the help of a light-barrier, step by step or continuously. As a result, one will make sure that the cut off sections of the sheet metal always pass through only a short stretch in their free drop, so that a neat, uniform stack will be formed.
(b) Description of the Prior Art
Although such an arrangement has in principle proven itself very well, still there is a significant disadvantage, whenever small sheet metal sections are made. Such a stack of small sections under certain circumstances only takes up a small part of the surface of a pallet, whereby it would be desirable, however, to place several such stacks side by side. As soon however, as the first stack is completed, the lifting table can no longer be driven up, since the existing stack would abut against the support. Therefore people had been forced hitherto either to leave the capacity of the pallet unused, by only forming one stack per pallet or by putting up with a second disordered stack beside it since the cut of sheet metal sections have to pass through relatively large a distance in a free drop.